Southern Ocean Region

The Southern Ocean is defined as the water that surrounds Antarctica ranging north to the Antarctic Convergence or Polar Front (50-60° S. latitude), and comprises between 10 and 15% of the world’s ocean water (Shotton 2005, Grant et al. 2006, CCAMLR). The various currents, gyres, eddies, and fronts of the Southern Ocean, combined with the annual formation and retreat of seasonal sea ice, create a unique, highly productive, marine environment. According to Small and Taylor (2006), the Convention on the Conservation of Antarctic Marine Living Resources (CCAMLR) Convention area is extremely important for breeding populations of short-tailed shearwaters and several species of albatrosses and petrels. Marine mammals in the southern Ocean have been exploited since the early 19th Century, thus making their populations vulnerable to any incidental takes that may occur today (FAO 2005). The IUCN Red list has identified 25 species of marine mammals that occur in the Southern Ocean, seven of which are caught incidentally to fishing activities in the area. Marine turtle species rarely venture as far south as the Southern Ocean and thus are not discussed in this report (Gulko & Eckert 2004). The two principal fisheries in the Southern Ocean are for Antarctic krill and Patagonian Toothfish (Shotton 2005). Gear types include trawls, gillnets, and longlines.

Currently, regulations exist that protect seals, whales, and seabirds from direct harvest. These species, however, are threatened with incidental mortality from interactions with trawls and longlines. Seabirds are most commonly captured by longlines, but available information regarding the capture of seabirds by trawls and gillnets is limited. Since 1989, conservation measures have been implemented to reduce incidental seabird mortality within the area under CCAMLR’s jurisdiction, including the use of weighted longlines and streamer lines, night-setting, and onboard waste retention (CCAMLR 2005). Although CCAMLR has reduced seabird mortality in the Convention Area by 99% since 1997 (Small 2005), this progress is threatened by the growth of illegal, unregulated and unreported (IUU) fisheries, as well as by fishing activity outside the Convention Area. (Weimerskirch et al. 1999, Kock 2001).